On Nov 15, 2008, at 5:02 PM, pong wrote: > > According to diveintopython .extend should be faster than + since the > former does not return a value. > I was curious and tried > > %timeit [ ]+[2] > 1000000 loops, best of 3: 741 ns per loop > and > > %timeit [ ].extend([2]) > 1000000 loops, best of 3: 870 ns per loop > > so + actually beats .extend slightly. > > I got the same result when I tried that on sage online. (however > %timeit only tried 625 loops instead of 10^7 loops, why?) > > Another puzzling thing is that > b=[ ] > %timeit b.extend([2]) > 1000000 loops, best of 3: 801 ns per loop > > type(b) > <type 'list'> > > but then when I run > > %timeit b+[2] > 10 loops, best of 3: 88.9 ms per loop > > That's much slower, in fact if you simple type b and hit enter... SAGE > hangs. > > why?
It is a function of how long the list is. Calling a.extend(b) avoid copying the list, but requires an attribute lookup and python call. As the list gets longer, extend gets faster. - Robert --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
